Sheet material containing a liquid for processing a silver halide layer



Nov. 4, 1952 E. H. LAND 2,616,804

SHEET MATERIAL CONTAINING A LIQUID FOR PROCESSING A SILVER HALIDE LAYERFiled Aug. 13, 1945 v 2 SHEETSSHEET l Phoiographic Reqgenf RemovableLiquid Remirfing Wal! Liquid Reiaining Wall Base Phoiographic FHComposih Liquid Coniuining ShQ i f IN VE TOR.

E. H. LAND SHEET MATERIAL CONTAINING A LIQUID FOR PROCESSING A SILVERHALIDE LAYER Filed Aug. 13, 1945 2 $HEETS-SHEET 2 4 I ro.|2 22.24

y 5 FIG. 4

FIG. 5

1 INVENT0R. t

Patented Nov. 4, 1952 SHEET MATERIAL CONTAINING A LIQUID FOR PROCESSINGA SILVER HALIDE LAYER Edwin H. Land, Cambridge, Mass, assignor toIPolaroid Corporation, Cambridge, Mass., a corporation of DelawareApplicationAugust .13, 1945, Serial No. 610,523

(oress) '18 Claims.

layer of material such, =for exampla as aphoto' sensitive emulsion, withsaid reagent.

Anotherobject of theinvention is to provide a novel sheet material oftheabove type wherein the liquid reagent is in layer form and iscontained in an envelope comprising a removable liquid-retainingmember,said sheet :material beingso .formed that when said retaining member isremoved and the remainder of the sheet is brought into face-to-iacecontact with a developable photosensitive emulsion containinga latentimage said image is developed.

.A- further object is .to:provide a novel composite sheet-material:oithe above character which is adapted to provide a positive print ofthe subject matter of the latent image.

Still-another object is :to providea novel composite fihn comprising, incombination, a photosensitive layer and the materials required forforming afixed positive image of the subject matter of a :latent imagein :said layer.

.Another object .is to provide a novel sheet material comprising a,permeable layer and means containing a liquid material out of contactwith said layer, said means being so constructed that said liquidmaterial-may be caused to selectively permeate a. predetermined area ofsaid permeable layer. 1 i

A :still .further object of the invention is to provide a novelmulti-ply photographic film comprising a photosensitive layer wherein alatent image may be .formed and a liquid layer coextensive with saidphotosensitive layer or at least theportion thereof containing saidimage, and adapted, when brought into .face-to-face contact with .saidphotosensitive layer, to develop said image.

' Another object of the invention is to provide a novel film or theabove type wherein the liquid layer provides a receiving layer for apositive image and contains ingredients which, when permeatedthrough'the photosensitive layer, provide an image-forming component insaid .receiving layer.

A further. object is to provide a novel sheet material adapted to serveas a base for a positive image and to act as part of a vapor-imperviousenvelope for the reagent which is employed to produce said image.

These and other objects of .the invention will in part be obvious'andwill in part appear hereinafter.

Theinventionaccordingly comprises the product possessing .the features,properties .and rela- 2 tion of components which are exemplified in theproduct hereinafter described and the scope of the application of whichwill "be indicated 'in the claims.

For a fuller understanding of the nature and objects of the invention,reference should be'had to the accompanying drawings wherein:

Figure l is a somewhat diagrammatic, transverse, sectional view of onetype of. sheet material comprehended 'by the present invention, thethicknesses .of the several layers of said film means being exaggeratedfor the purpose of clarity;

.2 is a .view similar to Fig. 1 through a longitudinal section of saidsheet material;

Fig. .3 is a view similar to Fig. 1 of a novel composite photographicfilm embodying the novel sheet material of the invention;

.Fig. 4 is a diagrammatic view of a camera apparatus wherein the novelliquid-containing sheet material of the present invention may beutilized to provide a fixed positive image of subject matter to which aphotosensitive film in said camera has been exposed; and

Fig.5 is a view similar to Fig. 4 of a type of camera apparatus whichmaybe employed in conjunction with the film means of Fig. 3.

According to the present invention, there is provided a novel compositesheet material comprising a layer of liquid reagent, 1. e., a layer of aliquid mixture or solution of materials useful particularly for thetreatment of photosensitive emulsions, said layer of reagent beingcoextensive with a predetermined area of said sheet and substantiallycoextensive in area with the area of the photosensitive emulsion to betreated thereby. The liquid reagent contains a filmforming substance insolution or in dispersion so that upon removal of the liquid content ofsaid layer, as .by evaporation or permeation into another layer, .alayer of solid material coextensive with the area .of said liquid'layeris obtained. The layer of solid material may be opaque or transparent,depending upon the composition of the reagent mixture .orsolution. Thefilm-forming material also acts to impart a desired high viscosity tothe reagent, the viscosity of said reagent being preferably in excess of5,000 centipoises.

In a preferred .iorm, .the liquid reagent comprises as a film-formingsubstance ahigh molecular weight polymeric plastic or protein, prei- 3solid layer formed by incorporating in the reagent mixture a suitablepigment such as titanium dioxide or a metallic flake such as aluminumfiake.

The layer of liquid material or reagent preferably has a suificientconcentration of the filmforming material and is sufficiently thin sothat when it is brought into contact with a layer of relativelypermeable material such as a layer of developable photosensitiveemulsion the latter layer may, by absorption of the liquid in thereagent, cause a substantially solid film to be formed in the place ofsaid liquid layer, said solid film being sufficiently stabledimensionally to receive. an image-forming component. The layer ofliquid reagent also preferably contains in solution one or moresubstances which, upon permeation of a photosensitive emulsioncontaining a latent image, are adapted to provide a component forforming an image of said latent image in an adjacent receiving layer.The image-forming component may be a complex soluble in the reagent andadapted to be transported at least in part by the reagent to thereceiving layer and reduced in the latter layer to give an insolubleproduct which forms the desired image. The component may also be a dyewhich is more substantive to the receiving layer than to the unexposed,undeveloped portions ofv the photosensitive layer and more substantiveto the developed portions of the photosensitive layer than to thereceiving layer. The component may be the oxidized developer and may actas a bleach to selectively bleach a dye with which the receiving layeris stained, said dye being initially incorporated in the reagent so asto form a uniformly dyed receiving layer.

One form of the novel sheet material of the invention is shown by way ofexample in the drawings, the thicknesses of the several layers of thecomposite sheet material being greatly exaggerated for the purpose ofclarity. As shown, said composite sheet material comprises a suitablebase It preferably of paper, as for example a kraft paper, upon whichthere is mounted a container IZ'in the form of an envelope which issubstantially coextensive with said base and which has contained thereina relatively thin layer of the photographic reagent. Envelope 12preferably comprises a pair of liquid-retaining walls IS an [8, upperwall l8 being readily removable from lower wall It. By removing upperwall IS, the layer of liquid reagent is exposed and may be brought intocontact, for example, with the photosensitive layer of a photographicfilm to provide an image-receiving layer adjacent said photosensitivelayer and to form in said receiving layer a fixed image of the subjectmatter of any latent image contained in the area of said photosensitivelayer in contact with said liquid reagent.

In order to normally retain the liquid reagent in the envelope withoutloss of the solvent of, the reagent, as by evaporation, and withoutoxidation of the reagent if the latter is susceptible to oxidation, itis preferable to form liquid-retaining walls I6 and E8 of materialswhich are substantially impervious to the liquid of the reagent, to thevapor of said liquid, and to oxygen. Where the solvent material in thereagent is water, the material of walls l6 and I8 may be a relativelywater-vapor-impervious plastic such as polyethylene or ethyl cellulose,or may be formed of a metal foil or a. metal foil coated with paraffin.In a preferred form, each of walls 16 and I8 is formed of a sheet ofmetal foil I 621, 18a, respectively, for example of lead or silver,provided on the inside surfaces thereof, 1. e., the surfaces adjoiningthe liquid reagent, with coatings 16b and [8b, respectively, of amaterial inert to an alkali as, for example, ethyl cellulose or amixture of ethyl cellulose and parafiln. Other satisfactory materialsfor coatings I61) and I8?) are the polyvinyl acetals such as thepolyvinyl acetal commercially identified by the trade name Alvar, thepolyvinyl butyral commercially identified as Butvar, and the polyvinylformal commercially identified as Formvar.

In the event that the liquid reagent layer I4 is adapted upon drying toform a solid film which is transparent, as for example when thefilmforming substance in said reagent is a transparent plastic such assodium carboxymethyl cellulose, it is desirable to incorporate incoating liib a suitable pigment such as titanium dioxide or a metallicfiake such as aluminum flake which is adapted to provide a whitebackground against which an image formed of silver or a dye in saidtransparent film may be visible.

Film l0, I2 may be employed for forming a positive print of the subjectmatter of a latent image contained in a photosensitive layer by havingretaining wall l8 removed and liquid layer It brought into face-to-facecontact with that portion of the photosensitive layer which contains thelatent image to be reproduced. The contact between the permeablephotosensitive layer and the liquid reagent causes the liquid content oflayer M to permeate into at least the surface portions of thephotosensitive layer adjacent said liquid layer and thus provides animage-forming component which is adapted to migrate from thephotosensitive layer to the remainder of layer It to form a positiveimage in the latter layer. The permeation of the liquid content of layerI4 into the photosensitive layer also acts to dry layer l4 and to formsaid layer into a dimensionally stable film so that the image obtainedin said layer from the image-forming component is an accuratereproduction of the latent image in the photosensitive layer. At thetermination of the period required for the formation and migration ofthe image-forming components, the remainder of layer [4 is separatedfrom the photosensitive layer and substantially fully dried in theatmosphere to provide a solid film containing a fixed image. Compositesheet l0, [2 may be provided for use in conjunction with a single frameof a photosensitive film as by having layer I4 formed of an areacorresponding substantially to the area of the film frame.

In this form, said composite sheet is particularly adapted for use withcut film either in a camera or in a dark room. Sheet I0, l2 may also beprovided in a strip of sufficient length to form fixed images of thelatent images contained in a plural-,

ity of frames of a photographic film. In the latter form, the compositesheet material of the invention may have the liquid layer extendcontmuously from frame to frame, or the liquid layer for each frame maybe contained in a separate envelope mounted. on a single base strip ora.

adapted to handle a plurality of image frames,

and as shown envelope walls l6, l8 are provided with a plurality oftransverse seals 20 at spaced intervals separated by a'distance equalapproxistream mately to the'leng'th of each ertn'e image irames withwhich the reagent layer is to coast. Each of seals 20 may be obtained byadhering together coatings I62) and 18b throughout-the width-of thesheet and along a predetermined length of said sheet preferably equal tothe spacing between the film frames of the photographic film with whichthe composite sheet is to be u'ltimately employed.

To form the novel composite sheet material 'of the invention,itispossible, for'exampl'e, to se= cure retaining wall l6 to base and tothereafter coat the surface of said retaining wallwitha layer of reagentof "the desired thickness. The reagent layer'is'then covered withretaining wall 18 and the latter adhered to retaining wall Itlongitudinally and transversely as by the applieation of ressure andheat orpressure alone, the seal being effected along the longitudinaledges of the sheet, and transversely where "desired. The reagent issufficiently "viscous to permit spreading thereof on the surface ofretaining wall IE to the desired thickness as by the'use of a doctorblade. It is also possible to 'emboss the area of wall l-S whichreceives layer M to provide a shallow trough for receiving and retainingthe reagent during assembly of the composit'e sheet. The thicknessoflayer I4 need not exceed .002 mm. and is preferably between 1002ahd-.0l1nm.thick. a

A reagent which is particularly suitable for use as layer Min thecomposite sheet material of the invention where the latter material isto'be employed in conjunction 'with photosensitive films comprising asilver halideemulslon is one which contains, in addition to the 'filmfor'ming agent, a developer and-a substance for forming asoluble silvercomplex withsilver halide. When the reagent is broughtinto contact witha photosensitive emulsion comprising a silver halide and containing alatent image, the developer and the complex-forming substance permeatesaid emul sion, reducing the exposed silver halide of thelatent image tosilver and reacting with "the unexposed'silverhalide to provide-asoluble silver complex. -At the same time, the film-forming component ofthereagent provides'a'permeable layer or sheet adjacent the emulsion'towhich the reagent transports at leasta part of the soluble silvercomplex and in which said complex is re= duced to an insoluble productcomprising silver to give the desired positive image.

Examples of suitable reagents of this type are given below, but itis to"be expressly understood that the examples are illustrative only, andthat the invention is not limited to the ma'terials Or the proportionsset out therein:

, rrhe sodium sulfiteflhydroquinone, and sodium thiosulfate aredissolved in the water, and the sodium carboxymethyl cellulose solutionis then added and thoroughly mixed therewith. The solution thus obtainedis cooledto a temperature between 65 and 75 and thereaiterthe'sodiumhydrexide solution is added thereto,

' 6 alternative method of obtaining the above reagent "is to firstdilute the sodium .carboxymethyl cellulose solution with the water andthereafter add the sodium sulfite, hydroquinone, and sodium thiosulfate.The mixing of these ingredients may be carried out at a temperaturebetween and F. and after the components are thoroughly mixed, themixture may be cooled to a temperature of approximately 65 to 75 F. andthe specified quantity of sodium hydroxide solution added thereto. I

The proportions of "the ingredients set out above may be varied withinrelatively wide limits as, for example, quantities of hydroquinone up to6.6 grams may be used. Similarly, the quantity of sodium thiosulfate maybe Varied from 1.4 to 2.8 grams, and the amount of sodium hydroxidesolution from '11 to 44 cc. While it preferred to omit the restrainerfrom the novel reagents of the invention, satisfactory results may beobtained by including, for example, 2.2 to 6.6 grams of potassiumbromide in the solution of the above example.

Sodiumthiosul-f M. g 1o Aqueous solution of medium viscosity'sodiumearboxymethyl cellulose consistingof '20 g. of the latter compound incc. of water mesa-"rang" 100 sodium hydroxide s rll i-i -i ;g 5.6

Example II I Watera--- l ah H- l -ra l ccs 100 Sodium sulfite 4.5 4.52.5 4.9

boxymethyl cellulose, sodium salt, medium viscosity, consisting of 35 g.of the latter compound in 100 cc. of waterernahlgh 30 Era'mple IV 7Water any. l-l -l vrecs. 100 Sodium sulfite-. a-.. -g 6 Hydroquinone r.l. g 6 Sodium thiosulfate l -g 3.3 Sodium hydroxide g c 3.6

Aqueous solution of Hercules or Dow carboxymethyl cellulose, sodiumsalt, medium viscosity, consisting of 35- g. of thelatter compound in100 cc. of water g 13.3

"Sodium alginate may beused instead of sodium carboxymethyl cellulose inany of the above ex-' amples in the same relative amounts as sodiumcarboxymethyl cellulose. Many of the starches, as for example Mercksstarch, Argo starch, Maine potato starch and Brazilian starch may alsobe used, and it is preferable when using these starches to employ aconcentration approximately twice that of the sodium carboxymethylcellulosesuggested above. It is also possible to utilize such othercellulosic ethers as hydroxyethyl cellulose, the latter being preferablyprovided in the reagent in somewhat higher concentration than the sodium'carboxymethyl cellulose. If a relatively'white and nontransparent filmis to be formed by the reagent, "there may beincorporated in saidreagent 9. suitable pigment such as titanium dioxide or. mixtures oftitanium dioxide and magnesium oxide or magnesium carbonate. Theaddition of titanium dioxide equivalent to from to 20% by weight of thereagent has given good results. These pigments also serve as fillersforincreasing the viscosity of the reagent.

Examples of other developers which may be used in the reagent arep-aminophenol hydrochloride (Kodelon), p-hydroxyphenylaminoacetic acid(Athenon, Glycin), p-phenylenediamine, pyrocatechin,diaminophenolhydrochloride (Amidol), pyrogallol, o-phenylenediamine andbromohydroquinone.

Examples of other materials which may be used in the reagent for thepurpose of forming a soluble silver complex with the undeveloped silverhalide of the photosensitive layer are ammonium thiosulfate and ammonia.For obvious reasons, it is preferable that the complex-forming substancebe one which does not desensitize the silver halide emulsion and onewhich is not toxic. For example, a compound such as sodium cyanide whichwill give satisfactory photographic results when used in the reagent inaccordance with the methods of the invention is generally not desirablebecause of its toxic character.

The liquid reagent may also contain other accelerators, as for examplepotassium hydroxide, sodium carbonate, borax, sodium metaborate,paraformaldehyde, trisodium phosphate or Triton B. In certainmodifications of the reagent composition, the restrainer as well as thepreservative may be omitted.

With the reagents set out in the above examples, satisfactory resultsare obtained if layer I4 has a thickness of approximately .005 mm.

The novel composite sheet material of the present invention may comprisepart of a unitary film structure which also includes a layer ofphotosensitive material. Referring to Fig. 3, there is illustrated byway of example one form of film means of this type, and as shown, saidfilm means comprises a suitable transparent film base 22, for example, acellulosic film base such as cellulose acetate, cellulose nitrate,cellulose acetate butyrate, or cellulose acetate propionate, whichserves as a support for a photosensitive emulsion 24 comprising a silverhalide. It is to be understood that the term photosensitive emulsioncomprising a silver halide as used herein is intended to include withinits scope an emulsion of a single. silver halide salt, an emulsion ofmixed silver halide salts, an emulsion of a silver mixed halide salt, oran emulsion of a mixture of the last-named salt with any of the others.Photographic film 22, 24 is mounted on composite sheet l0, I2 withretaining wall 18 adjoining photosensitive layer 24.

' A novel arrangement of elements whereby sheet material l0, l2 may beused in conjunction with a photographic film comprising a plurality offilm frames, each of which is adapted to be exposed and to have a latentimage formed therein, is shown diagrammatically in Fig. 4. In the formillustrated, said apparatus comprises asuit: able mechanism for removingthe liquid-retaining wall 18 froma roll 30 of sheet material 10, i2 as,for example, an idler roll 32 and a take-up roll 34, the latter beingdrivably connected by a suitabl friction drive (not shown) to a pair ofpressure rollers 36. Rollers 36 are preferably provided adjacent toidler roll 32 and composite sheet l0, l2, without the portion ofretaining wall l8 which has been removed by the above mechanism, isadapted to be fed between said pressure rollers and brought intoface-to-face contact with an exposed frame of the photosensitive layerof a photographic film 31. It will be understood that theabove-described apparatus may be provided in a dark room or used in asuitable light-tight housing. In the form illustrated, the severalelements comprising said mechanism are embodied in an attachment A for acamera, ,0 wherein photographic film 31 may be fed between rollers 36 asit is metered from exposure position E by the film driving mechanism ofsaid camera.

It is desirable to embody within or connect to said attachment suitablemeans wherein the assembly obtained between rollers 36 is retained indarkness after it passes through said rollers and from which saidassemply may be removed without exposing the interior of the camera tolight. To this end, chamber 38 is preferably provided adjacent to thepressure-rollers and is connected to the interior of the camera by asuitable light-tight recess 40 lined, for example, with a material suchas felt. The assembly which is formed between rollers 36 is meteredtherefrom into said chamber through said opening, and is retained insaid chamber during th formation of the positive image. One wall 42 ofsaid chamber is preferably pivotally mounted to serve as a closure andin closed position does not admit any light into the chamber. However,said wall 42 may be opened to permit the severance and the removal ofthe frame of film retained in the chamber. In operation, therefore, thefilm assembly which is formed between rollers 36 passes through opening40 into chamber 38 and after the entire frame has passed into saidchamber it is retained therein in the absence of actinic light for suchtime as is necessary to effect the formation of the positive image as,for example, thirty seconds. Thereafter, wall 42 is pivoted outwardly toopen the interior of the chamber and the assembly of said materials issevered and removed from the chamber.

A form of camera apparatus wherein the novel composite film means ofFig. 3 may be utilized is shown diagrammatically in Fig. 5 as comprisingmeans for mounting roll 50 of said film, from which said film may be fedto exposure position E. After being exposed, the film is metered over aroll 52 and is so threaded that liquid-retaining wall [8 thereof isadapted to be Wound upon a take-up roll 54 which is connected by meansof a friction drive to a pair of pressure rollers 56. Take-up roll 54 ispreferably located to one side of th path of travel of th remainder ofliquidcontaining sheet l0, l2 (identified as 58 in Fig. 5), as thelatter moves from the point at which layer I8 is stripped therefrom tothe point at which photosensitive layer 24 of film 22, 24 is broughtinto contact therewith. As a result of this arrangement,liquid-containing sheet [0, l2, once placed in condition for release ofthe liquid, does not contact any material except the photosensitivelayer of film 22, 24. It is desirable to provide suitable guide meanssuch as a plurality of rollers 60 for film 22, 24 as the later travelsfrom roller 52 to rollers 56, avoiding take-up rollers 54.

After the separated portions I0, l2 and 22, 24 of the composite film arebrought into face-toface contact between pressure rollers 56, theassembly thus formed passes from the main chamber of the camera into asuitable light-tight chamber formed, for example, of a flat, rectangularcontainer 62 detachably secured to the camera. The passage of the sheetmaterials from the main; camera chamber into container 62 is effectedthrough an opening which connects said chamber and said container andwhich has its walls suitably lined to prevent admission oflight intosaid main chamber whenever said container is removed. After the assemblyformed by the separated portions of the film is fed through pressurerollers 56 into container 62, and a sufficient length of time haselapsed to form the fixed positive image in the receiving layer,container 62 is removed from the camera, exposing the assembly. Thelatter may then be severed from the remainder of the film. and thereceiving layer formed from layer It and supported on envelope wall l6and base I!) may be separated from, the photosensitive layer 24 of film22, 24.

Since certain changes may be made in the above product and differentembodiments of the invention could be made without departing from thescope thereof, it is intended that all matter contained in the abovedescription or shown in the accompanying drawings shall be interpretedas illustrative and not in a limiting sense.

The term liquid as used herein is intended toinclude material in arelatively plastic state, i. e., materials capable of being deformedcontinuously and permanently in any direction without rupture under astress exceeding the yield value.

Other inventions which are related to the invention set forth herein andwhich, like the present invention, are the property of a common assigneeare applications of Edwin H. Land, Serial No. 64,870, filed December 11,1948, now Patent No. 2,543,181; Edwin H. Land, Serial No. 700,931, filedOctober 3, 1946; and Edwin E. Land, Serial No. 728,983, filed February1'7, 1947.

It is also to be understood that the following claims are intended tocover all of the generic and specific features of the invention hereindescribed, and all statements of the scope of the invention which, as amatter of language, might be said to fall therebetween.

'What' is claimed is:

1. A" storable, externally dry product for developing a photosensitivesilver halide element, said product comprising a liquid layer includinga liquid having dispersed therein a "thickening agent for substantiallyincreasing the viscosity thereof and at least one photographic reagentfrom the class consisting of the silver halide developers and the silverhalide solvents, said liquid layer containing in each unit area thereofan amountof liquid suflicient to render said reagent effective forprocessing an equivalent unit area oi? a photosensitive silver halideelement, a pair of solid layers impervious to the liquid of. said liquidlayer and superposed on opposite sides thereof, said liquid-impervioussolid layers extending beyond the margins of said liquid layer and beingsealed together adjacent said margins to. form an envelope for saidliquid layer, said envelope: having a cavity for said liquid layer whichis very thin in relation to its length and breadth and which iscontinuous in a direction perpendicular to its thickness throughout anarea at least equal to the area of the silver halide element to beprocessed, one of said liquid-impervious layers being strippable fromthe remainder of said product to expose substantially the entire area ofsaid thin layer for direct contact with a photosensitive silver halideelement, said cavity maintaining said liquid layer distrib- 0 uted as athin layer so that no redistribution of the liquid mass of said liquidlayer, either lengthwise or breadthwise, is required to render saidliquid layer efiective to process said element upon the removal of saidstrippable layer.

2. The product of claim 1 wherein said liquid layer is arranged toprovide an image-receiving layer by providing, as said thickening agent,a solid material which gives a solid residual film upon removal of theliquid content of said liquid layer.

3. The product of claim 1 wherein said thickening agent comprises analkali-inert high molecular weight polymer and said liquid includes asilver halide developer, a silver halide solvent and an akali.

4. The product of claim 1 wherein said liquid layer is arranged toprovide an image-receiving layer by providing, as said thickening agent,a film-forming material which dries to a solid film upon removal of theliquid contents thereof, said liquid layer including a pigment forrendering said image-receiving layer white and opaque.

5. The product of claim 1 wherein said liquid includes an organiccolloid, a silver halide solvent, an alkali and a white pigment.

6. The product of claim 1 wherein each of said liquid-impervious layersincludes a stratum of metallic foil.

7. The product of claim 1 wherein said two liquid-impervious layers aresealed together transversely thereof along a plurality of longitudinallyspaced lines so as to provide a series of said envelopes, each envelopeconfining a portion of said liquid layer which is spaced, by a pair ofsaid transverse seals, from its adjacent portions of said liquid layer.

8. A storable, externally dry product comprising a photosensitive silverhalide element and means for processing said element, said meanscomp-rising a liquid layer having dissolved therein a thickening agentfor substantially increasing the viscosity thereof, a silver halidesolvent and a silver halide developer, said liquid layer beinghomogeneous throughout its depth and containing in each unit areathereof an amount of liquid sufficient to render said developereffective for developing an equivalent unit area of the photosensitivelayer of said photosensitive silver halide element, a pair of solidlayers impervious to the liquid of said liquid layer and superposed onopposite sides thereof, said liquidimpervious solid layers extendingbeyond the margins of said liquid layer and being sealed togetheradjacent said margins to form an envelope for said liquid layer, one ofsaid liquidimpervious layers being strippable from the remainder of saidmeans to expose the liquid layer for direct contact with said silverhalide element, said silver halide element being connected to said meansso as to be superposable with said liquid layer after removal of saidstrippable layer.

9. The product of claim 8 wherein the portion of said means to which thephotosensitive element is connected includes a white pigment for forminga background for a positive transfer image in silver formed in saidliquid layer.

10. A photographic product comprising a photographic photosensitivesilver halide element, a liquid layer superposed with respect to saidphotosensitiveelement, said liquid layer extending over a predeterminedarea of said photosensitive element, and a pair of solid layersimpervious to the liquid of said liquid layer superposed on each sidethereof, said impervious layers being sealed together adjacent themargins of said liquid layer to form an envelope for said liquid layer,one of said impervious layers being located between said liquid layerand said photosensitive element and being strippable from both saidphotosensitive element and said liquid layer so that said one imperviouslayer can be removed to permit said liquid layer to contact said photosensitive element and transfer liquid thereto, said product havingpositioned therein at least one photographic processing material fromthe class consisting of the silver halide developers and the silverhalide fixers, said processing material being rendered effective upontransfer of liquid from said liquid layer to said photosensitive elementto carry out said transformation in said photosensitive element.

11. A photographic product comprising a photosensitive silver halideelement, a liquid layer superposed with respect to said photosensitiveelement, said liquid layer providing, upon drying, a solid film arrangedto serve as an image-receiving layer, and a pair of layers impervious tothe liquid of said liquid layer superposed on each side thereof, saidimpervious layers being sealed together adjacent the margins of saidliquid layer to form an envelope for said liquid layer, one of saidimpervious layers being located between said liquid layer and saidphotosensitive element and being strippable from both saidphotosensitive element and said liquid layer so that said one imperviouslayer can be removed to permit said liquid layer to contact saidphotosensitive element and transfer liquid thereto, said product havingpositioned therein photographic processing material, including a silverhalide developer, for developing said photosensitive element andproviding an image by transfer on said image-receiving layer, saidmaterial being rendered efiective, upon transfer of liquid from saidliquid layer to said photosensitive element, to process saidphotosensitive element, said liquid and said material being suflicientin amount to develop a latent image in the photosensitive element and toprovide said imagereceiving layer with a transfer image.

12. The product of claim 11 wherein said liquid includes a solution ofsaid developer and a silver halide solvent.

13. The product of claim 11 wherein said liquid layer is arranged toprovide an imagereceiving layer by having therein a solid material whichgives a solid residual film upon removal of the liquid content of saidliquid layer, said liquid layer including a pigment for rendering saidimage-receiving layer white and opaque.

14. The product of claim 11 wherein said liquid layer includes analkali-inert high molecular weight polymer, a silver halide solvent andan alkali.

15. The product of claim 11 wherein said liquid includes an organiccolloid, a silver halide solvent, an alkali and a white pigment.

16. The product of claim 11 wherein each of said liquid-imperviouslayers includes a stratum of metallic foil.

17. The product of claim 11 wherein said two liquid-impervious layersare sealed together transversely thereof along a plurality oflongitudinally spaced lines so as to provide a series of flat envelopes,each envelope confining a portion of said liquid layer which is spaced,by a pair of said transverse seals, from its adjacent portions of saidliquid layer.

18. The product of claim 11 wherein said liquid includes said silverhalide developer, a silver halide solvent, an alkali and sodiumcarboxymethyl cellulose, said liquid having a viscosity in excess of5000 centipoises.

EDWIN H. LAND.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 416,019 Thum Nov. 26, 1889417,400 Thum Dec. 17, 1889 431,537 Trenner July 1, 1890 447,121 StecherFeb. 24, 1891 671,961 Heinritz Apr. 16, 1901 693,536 Baker Feb. 18, 1902740,076 Baker Sept. 29, 1903 786,535 Thornton et a1 Apr. 4, 1905 935,115Kelly et a1. Sept. 28, 1909 1,207,042 Hochstetter Dec. 5, 1916 1,277,048Brayer Aug. 27, 1918 1,360,624 Dodge Nov. 30, 1920 2,013,159 Lierg Sept.3, 1935 2,196,901 Ham Apr. 9, 1940 2,214,446 Albers Sept. 10, 19402,315,966 Knott Apr. 6, 1943 2,320,108 Tull May 25, 1943 2,322,005Fierke et al. June 15, 1943 2,322,006 Fierke et al June 15, 19432,322,027 Jelley June 15, 1943 2,323,246 Schneider et al. June 29, 19432,328,034 Sease et al. Aug. 31, 1943 2,336,902 Tull Dec. 14, 19432,350,380 White June 6, 1944 2,352,014 Rott June 20, 1944 2,365,345Kirby Dec. 19, 1944 2,369,171 Murray Feb. 13, 1945 FOREIGN PATENTSNumber Country Date 1,201 Great Britain Jan. 26, 1888 17,738 GreatBritain of 1899 9,248 Great Britain of 1905 26,066 Great Britain Dec.30, 1905 8,911 Great Britain July 12, 1906 24,667 Great Britain Nov. 3,1906 13,835 Great Britain 1907 328,762 Great Britain May 8, 1930 370,821Germany May 25, 1921 115,331

Switzerland June 16, 1926

1. A STORABLE, EXTERNALLY DRY PRODUCT FOR DEVELOPING A PHOTOSENSITIVESILVER HALIDE ELEMENT, SAID PRODUCT COMPRISING A LIQUID LAER INCLUDING ALIQUID HAVING DISPERSED THEREIN A THICKENING AGENT FOR SUBSTANTIALLYINCREASING THE VISCOSITY THEREOF AND AT LEAST ONE PHOTOGRAPHIC REAGENTFROM THE CLASS CONSISTING OF THE SILVER HALIDE DEVELOPERS AND THE SILVERHALIDE SOLVENTS, AND LIQUID LAYER CONTAINING IN EACH UNIT AREA THEREOFAN AMOUNT FOR PROCESSING AN EQUIVALENT UNIT AREA EFFECTIVE FORPROCESSING AN EQUIVALENT UNIT AREA OF A PHOTOSENSITIVE SILVER HALIDEELEMENT, A P AIR OF SOLID LAYERS HALIDE ELEMENT, A PAIR LIQUID LAYER ANDSUPERPOSED ON OPPOSITE SIDES THEREOF, SAID LIQUID IMPERVIOUS SOLODLAYERS EXTENDING BEYOND THE MARGINS OF SAID LIQUID LAYER AND BEINGSEALED TOGETHER ADJACENT SAID MARGINS TO FORM AN ENVELOPE FOR SAIDLIQUID LAYER, SAID ENVELOPE HAVING A CAVITY FOR SAID LIQUID LAYER WHICHIS VERY THIN IN RELATION TO ITS LENGTH AND BREADTH AND WHICH ISCONTINUOUS IN A DIRECTION PERPENDICULAR TO ITS THICKNESS THROUGHOUT ANAREA AT LEAST EQUAL TO THE AREA OF THE SILVER HALIDE ELEMENT TO BEPROCESSED, ONE OF SAID LIQUID-IMPERVIOUS LAYERS BEING STRIPPABLE FROMTHE REMAINDER OF SAID PRODUCT TO EXPOSE SUBSTANTIALLY THE ENTIRE AREA OFSAID THIN LAYER FOR DIRECT CONTACT WITH A PHOTOSENSITIVE SILVER HALIDEELEMENT SAID CAVITY MAINTANING SAID LIQUID LAYER DISTRIBTED AS A THINLAYER SO THAT NO REDISTRIBUTION OF THE LIQUID MASS OF SAID LIQUID LAYER,EITHER LENGTHWISE OR BREADTHWISE, IS REQUIRED TO RENDER SAID LIQUIDLAYER EFFECTIVE TO PROCESS SAID ELEMENT. UPON THE REMOVAL OF SAIDSTRIPPABLE LAYER.
 8. A STORABLE, EXTERNALLY DRY PRODUCT COMPRISING APHOTOSENSITIVE SILVER HALIDE ELEMENT AND MEANS FOR PROCESSING SAIDELEMENT, SAID MEANS COMPRISING A LIQUID LAYER HAVING DISSOLVED THEREINGA THICKENING AGENT FOR SUBSTANTIALLY INCREASIN THE THICKENING AGENT FORSUBSTANTIALLY INCREASAND A SILVER HALIDE DEVELOPER, SAID LIQUID LAYERBEING HOMOGENOUS THROUGHOUT ITS DEPTH AND CONTAINING IN EACH UNIT AREATHEREOF AN AMOUNT OF LIQUID SUFFICIENT TO RENDER SAID DEVELOPEREFFECTIVE FOR DEVELOPING AN EQUIVALENT UNIT AREA OF THE PHOTOSENSITIVELAYER OF SAID PHOTOSENSITIVE SILVER HALIDE ELEMENT, A PAIR OF SOLIDLAYERS IMPERVIOUS TO THE LIQUID OF SAID LIQUID LAYER AND SUPERPOSED ONOPPOSITE SIDES THEREOF, SAID LIQUIDIMPERVIOUS SOLID LAYERS EXTENDINGBEYOND THE MARGINS OF SAID LIQUID LAYER AND BEING SEALED TOGETHERADJACENT SAID MARGINS TO FORM AN ENVELOPE FOR SAID LIQUID LAYER, ONE OFSAID LIQUIDIMPERVIOUS LAYERS BEING STRIPPABLE FROM THE REMAINDER OF SAIDMEANS TO EXPOSE THE LIQUID LAYER FOR DIRECT CONTACT WITH SAID SILVERHALIDE ELEMENT, SAID SILVER HALIDE ELEMENT BEING CONNECTED TO SAID MEANSSO AS TO BE SUPERPOSABLE WITH SAID LIQUID LAYER AFTER REMOVAL OF SAIDSTRIPPABLE LAYER.